Editing Canopus (section)

== Evolution ==
The spectrum of Canopus indicates that it spent some 30 million years of its existence as a blue-white main sequence star <!-- source suggests B2V but may be too exact --> of around 10 solar masses, before exhausting its core hydrogen and [[Stellar evolution|evolving]] away from the [[main sequence]].<ref>{{cite journal |last1=Peimbert |first1=M. |last2=Wallerstein | first2= G.| last3= Pilachowski | first3= C. A. |title=An upper limit for the deuterium abundance in Canopus |journal=Astronomy and Astrophysics |date=1981 |volume=104 |issue=1 |pages=72–74 | bibcode=1981A&A...104...72P}}</ref> The position of Canopus in the [[H–R diagram]] indicates that it is currently in the core-helium burning phase.<ref name=vlti/>  It is an intermediate mass star that has left the [[red-giant branch]] before its core became [[degenerate matter|degenerate]] and is now in a [[blue loop]].<ref name=desouza>{{Cite journal | last1 = Domiciano De Souza | first1 = A. | last2 = Bendjoya | first2 = P. | last3 = Vakili | first3 = F. | last4 = Millour | first4 = F. | last5 = Petrov | first5 = R. G. | title = Diameter and photospheric structures of Canopus from AMBER/VLTI interferometry | doi = 10.1051/0004-6361:200810450 | journal = Astronomy and Astrophysics | volume = 489 | issue = 2 | pages = L5–L8 | year = 2008 |bibcode = 2008A&A...489L...5D | url = https://hal.archives-ouvertes.fr/hal-00316994/document | doi-access = free }}</ref>  Models of stellar evolution in the blue loop phase show that the length of the blue loop is strongly affected by rotation and mixing effects inside the star.  It is difficult to determine whether a star is currently evolving towards hotter temperature or returning to cooler temperatures, since the evolutionary tracks for stars with different masses overlap during the blue loops.<ref name=smiljanic2006>{{cite journal |bibcode=2006A&A...449..655S |title=CNO in evolved intermediate mass stars |last1=Smiljanic |first1=R. |last2=Barbuy |first2=B. |last3=De Medeiros |first3=J. R. |last4=Maeder |first4=A. |journal=Astronomy and Astrophysics |year=2006 |volume=449 |issue=2 |page=655 |doi=10.1051/0004-6361:20054377 |arxiv=astro-ph/0511329 |s2cid=3711409 }}</ref>

Canopus lies on the warm side of the [[instability strip]] and does not pulsate like [[Cepheid variables]] of a similar luminosity.<ref name=ayres2011>{{cite journal |doi=10.1088/0004-637X/738/2/120 |title=The Curious Case of the Alpha Persei Corona: A Dwarf in Supergiant's Clothing? |year=2011 |last1=Ayres |first1=Thomas R. |journal=The Astrophysical Journal |volume=738 |issue=2 |page=120 |bibcode=2011ApJ...738..120A |doi-access=free }}</ref>  However its atmosphere does appear to be unstable, showing strong signs of convection.<ref name=smiljanic2006/>

Canopus may be massive enough to explode by an [[Type II supernova|iron-core collapse supernova]].